Aphantasia: The science of visual imagery extremes
Abstract
Visual imagery allows us to revisit the appearance of things in their absence and to test out virtual combinations of sensory experience. Visual imagery has been linked to many cognitive processes, such as autobiographical and visual working memory. Imagery also plays symptomatic and mechanistic roles in neurologic and mental disorders and is utilized in treatment. A large network of brain activity spanning frontal, parietal, temporal, and visual cortex is involved in generating and maintain images in mind. The ability to visualize has extreme variations, ranging from completely absent (aphantasia) to photo-like (hyperphantasia). The anatomy and functionality of visual cortex, including primary visual cortex, have been associated with individual differences in visual imagery ability, pointing to a potential correlate for both aphantasia and hyperphantasia. Preliminary evidence suggests that lifelong aphantasia is associated with prosopagnosia and reduction in autobiographical memory; hyperphantasia is associated with synesthesia. Aphantasic individuals can also be highly imaginative and are able to complete many tasks that were previously thought to rely on visual imagery, demonstrating that visualization is only one of many ways of representing things in their absence. The study of extreme imagination reminds us how easily invisible differences can escape detection.
Authors
- Rebecca Keogh14
- Joel Pearson28
- Adam Zeman14
Understanding Visual Imagery Extremes: Aphantasia and Hyperphantasia
Overview/Introduction
Methodology
- Questionnaires: Participants described their ability to visualize using tools like the Vividness of Visual Imagery Questionnaire (VVIQ).
- Objective Tests: Tasks like the binocular rivalry paradigm assessed visual imagery strength.
- Neuroimaging: Brain scans helped identify which areas are active during visualization.
Key Findings
- Brain Activity: A network involving the frontal, parietal, temporal, and visual cortex is crucial for generating mental images.
- Individual Differences: The ability to visualize is linked to the anatomy and function of the visual cortex. Aphantasia may be connected to conditions like prosopagnosia (difficulty recognizing faces) and reduced autobiographical memory, while hyperphantasia is associated with synesthesia (a condition where senses overlap).
- Imagery and Imagination: Despite lacking visual imagery, aphantasic individuals can still be highly imaginative, suggesting that visualization is just one way to represent absent things.
Implications
- Cognitive Processes: Understanding visual imagery extremes can shed light on how we process memories and experiences.
- Mental Health: Imagery plays roles in neurological and mental disorders, and knowing more about these extremes could improve treatments.
- Creativity and Problem-Solving: Aphantasia doesn't hinder creativity; some highly successful individuals attribute their achievements to this condition.
Limitations
- Subjectivity: Much of the data relies on self-reported experiences, which can be subjective.
- Lack of Longitudinal Studies: More research is needed to understand how these conditions develop and change over time.